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Earthquake Engineering

Seismic Retrofitting of Buildings

A large number of existing buildings do not have adequate earthquake resistant features as specified as in IS Codes. This is because of some reasons like non availability of competent technical manpower, lack of regulatory mechanisms to check earthquake resistance of proposed constructions and economic constraints.

Earthquake creates great devastations in terms of life, money and failure of structure. It is very important to upgrade certain building systems to make them more resistant to seismic activity. The structures can be earthquake damaged or earthquake vulnerable. Retrofitting proves to be a better economic consideration and immediate shelter to problems rather than replacement of the building. Retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. Retrofitting techniques are also applicable for other natural hazards such as cyclones, tornadoes and wind forces.

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Earthquake Resistant Buildings

Earthquake causes ground motions in a random fashion, both horizontally and vertically in all directions from the epicenter. As a result, the structures found in the ground vibrate, inducing inertial forces on them. It is therefore essential to ensure stability, strength, and serviceability with acceptable levels of safety by suitable design and detailing.

Due to horizontal shaking of the ground, horizontal inertia forces are generated at the level of the mass of the structure. The lateral inertia forces are transferred by the floor slab to the walls or columns, to the foundations, and finally to the soil. So each of the structural elements like floor slabs, walls, columns, foundations, and connections between them must be designed to safely transfer these inertia forces through them.

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Seismic Method of Analysis

INTRODUCTION
Seismic method of analysis is done in order to ascertain the various responses of buildings during earthquake and also to adopt the retrofitting of structures. It is an important tool for earthquake prone areas like Japan, North-East of India, Nepal, Philippines, and many more. This method of analysis is also important for design of elements of RCC buildings like beam, column, slab which are designed in accordance to IS 13920:2016. The seismic forces are dynamic in nature and these forces are tested for load carrying capacity, ductility, dampness, stiffness and mass. IS 1893:2016 is used to carry out seismic analysis of multi-storeyed building.
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Is Your Home Earthquake Resistant?

By
Technical paper Presented by:
Mr.Jismon Issac B.E (Mech) A.I.E, MBA

Over the past few years, India has seen a spurt in the vertical growth of buildings. They range from individual houses to very tall skyscrapers. Whenever news on earthquake is reported, we have only one question in our mind – Is our home safe during an earthquake?

Engineers always tell us that earthquake don’t kill, but that will be done by poorly built constructions. Earthquake resistant buildings can be made, only by constructing our homes with ductile character. For a better understanding in earthquake resistant buildings, we must acquire knowledge about earthquakes and its occurrence. The points are given as below;

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Seismic Vulnerability Assessment of School Buildings

SEISMIC VULNERABILITY ASSESSMENT of SCHOOL BUILDINGS: GAZA STRIP SCHOOLS as a CASE STUDY
BY
S. M. Shehada 1, S. Q. Shurrab 2
1,2 Department of Civil Engineering, Islamic University of Gaza, Gaza Strip, Palestine

Abstract
This study introduces a new approach for seismic assessment of existing school buildings. The proposed approach requires minimum human effort as it can be implemented by a small team of technical construction background. The approach is based on EMS-98 scale in addition to rapid survey of architectural and structural elements of existing school buildings. The study uses 64 selected public school buildings sampled from a total of 364 schools in Gaza Strip. The results showed that 50% of the surveyed schools are classified as Vulnerability class B, while 20 % are classified as Vulnerability Class A. The results were verified using the ‘probability matrix damage’ approach and showed good satisfying convergence. The results of the study are beneficial for the responsible parties who are expected to take appropriate actions related to enhancing seismic performance of Gaza Strip schools against seismic activities, due to the fact that these school buildings not only host about 450,000 students and teachers, but also serve as emergency shelters for those who lose their homes as a result of political instabilities in the region.

Keywords: Damage, Vulnerability, EMS-98, Seismic risk, structural type.

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